Hydrogen fuel cells are regarded as a promising new carbon mitigation strategy to realize carbon neutrality. The exploitation of robust and efficient cathode catalysts is thus vital to the commercialization of proton exchange membrane fuel cells (PEMFCs). Herein, we demonstrate a facile and scalable surface engineering route to achieve superior durability and high activity of a Pt-based material as a PEMFC cathode catalyst through a controllable liquid-phase reduction approach. The proposed surface engineering strategy by modifying Pt/C reduces the oxygen content on the carbon support and also decreases the surface defects on Pt nanoparticles (NPs), which effectively alleviate the corrosion of carbon and inhibit the detachment, agglomeration, and growth of Pt NPs. The resulting catalyst exhibits superior durability after a 10,000 potential cycling test in an acid electrolyteoutperforming commercial Pt/C. Moreover, the catalyst also demonstrates an improved oxygen reduction reaction (ORR) activity in comparison to commercial Pt/C by virtue of the high content of metallic Pt and the weakened Pt–OH bonding that releases more Pt active sites for ORR catalysis. Most importantly, the developed catalyst shows outstanding PEMFC performance and excellent long-term durability over 50 h of a constant-current test and 100 h of a load-cycling operation. This effective route provides a new avenue for exploiting robust Pt-based catalysts with superior activity in practical applications of PEMFCs.

Renewable power-derived green hydrogen distributed via natural gas networks is considered one of the viable routes to drive the decarbonization of transportation and distributed power generation, while a trace amount of sulfur impurities is one of the key factors that affect the durability and life cycle expense of proton-exchange membrane fuel cells (PEMFCs) for end users. Herein, we explore the underlying effect of sulfur resistance for Ptbased hydrogen oxidation reaction (HOR) electrocatalysts devoted to high-performance and durable PEMFCs. Two typical electrocatalysts, Pt/C with pure Pt nanoparticles (NPs) and PtCo/C with Pt 3 Co-alloy-core-Pt-skin NPs, were investigated to demonstrate the structure−property relation for Pt-based electrocatalysts. It was revealed that the PtCo/C demonstrated alleviated sulfur poisoning with the adsorption rate constant reduced by 21.7% compared with Pt/C, and the desorption of the adsorbed sulfur was also more favorable with Pt−S bond decomposition temperature lowered by approximately 25 °C. Characterization indicated that sulfur was predominantly adsorbed in the edge mode for PtCo/C, but in a comparable edge and bridge mode for Pt/C, which caused the strengthened Pt−S binding by the chelation effect for Pt/C. The lowered d-band center of surface Pt for PtCo/C, tuned by electron transfer from Co to Pt and Pt lattice strain, was also found responsible for the weakened Pt−S interaction. The recovery test based on electro-oxidation suggested that PtCo/C also outperformed Pt/C with faster and more thorough release of HOR active sites. The SO 42− species derived from electro-oxidation of S 2− was more apt to adsorb on Pt/C than PtCo/C because of its stronger affinity to SO 4 2− caused by the higher d-band center of Pt. Therefore, it is clarified that adequate modification of the Pt d-band center, for example, negatively tuned for the state-of-the-art Pt/C, is crucial to improve the sulfur resistance and recovery capability for Pt-based electrocatalysts while reserving comparable HOR activity. In particular, the investigated PtCo/C electrocatalyst is a better choice over Pt/C for more durable PEMFC anodes.

The high durability of proton exchange membrane fuel cells (PEMFCs) is crucial for their large-scale application in hydrogen mobility, while a trace amount of chloride in air significantly affects the durability of PEMFCs. Herein, we demonstrate a type of chloride-tolerant PtCo/C catalyst with a Pt3Co-core@Pt-skin structure showing that the chloride adsorption rate decreased by 34% compared with Pt/C. The introduction of Co weakens chloride adsorption on Pt with a decrease of ≥13% in the adsorption energy due to the downshifted Pt d-band center. The durability of PtCo/C outperforms that of Pt/C, exhibiting a stronger resistance toward the coupling effect of dynamic high-potential/chloride poisoning by mitigating Pt dissolution and hindering the Ostwald ripening of Pt nanoparticles. The presence of chloride aggravates the decay of Pt-based catalysts under the simulated potential cycling operation, and the aggravated effect is less severe for PtCo/C with an ∼40% decrease in the decay percentage in comparison to Pt/C after a 10,000-cycle test. This work provides a valuable guide for the design of robust antipoisoning catalysts by adjusting the Pt d-band center for long-life PEMFC application.

Hydrogen used in proton exchange membrane fuel cells (PEMFCs) mainly originates from refinery resources in which inevitable S-containing impurities possibly reduce the fuel cell life. Herein, the poisonous influence of trace impurities of H 2 S, carbon disulfide (CS 2 ), and carbonyl sulfide (COS) on the performance of Pt/C catalysts in hydrogen oxidation reaction (HOR) is investigated by a combination of electrochemical measurements, structural characterization, and DFT calculations. Rotating disk electrode (RDE) half-cell electrochemical experiments were used to determine the impact of H 2 S, CS 2 , and COS on the HOR activity and the recovery capability of a commercial Pt/C catalyst. The experimental results indicate that CS 2 even poses a more severe threat to the HOR activity than H 2 S, while COS poses a weaker threat than H 2 S. Moreover, all of H 2 S, CS 2 , and COS have a deteriorative impact on the regeneration of Pt/C catalysts. The theoretical calculation results reveal that CS 2 and COS can decrease the activity of HOR by decreasing the d-band center of Pt atoms except for occupying the active sites of Pt, while H 2 S deactivates the catalyst solely by occupying the active sites. Based on the analysis, the presence of trace CS 2 and COS, as well as H 2 S, will result in the serious degeneration of the Pt/C catalysts. These results provide insights into the deactivation mechanism of Pt-based catalysts and are significant for the practical applications of PEMFCs.

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High quality of hydrogen is the key to the long lifetime of proton-exchange membrane fuel cell (PEMFC) vehicles, while trace H2S impurities in hydrogen significantly affect their durability and fuel expense. Herein, we demonstrate a robust PtRu alloy catalyst with an intriguing H2S tolerance as the PEMFC anode, showing a stronger antipoisoning capability toward hydrogen oxidation reaction compared with the Pt/C anode. The PtRu/C-based single PEMFC shows approximately 14.3% loss of cell voltage after 3 h operation with 1 ppm of H2S in hydrogen, significantly lower than that of Pt/C-based PEMFCs (65%). By adopting PtRu/C as the anode, the H2S limit in hydrogen can be increased to 1.7 times that of the Pt/C anode, assuming that the PEMFC runs for 5000 h, which is conductive for the cost reduction of hydrogen purification. The three-electrode electrochemical test indicates that PtRu/C exhibits a slower adsorption kinetics toward S2– species with poisoning rates of 0.02782, 0.02982, and 0.03682 min–1 at temperatures of 25, 35, and 45 °C, respectively, all lower than those of Pt/C. X-ray absorption fine structure spectra indicate the weakened Pt–S binding for PtRu/C in comparison to Pt/C with a longer Pt–S bond length. Density functional theory calculation analyses reveal that adsorption energy of sulfur on the Pt surface was reduced for PtRu/C, showing 1–10% decrease at different Pt sites for (111), (110), and (100) planes, which is ascribed to the downshifted Pt d-band center caused by the ligand and strain effects due to the introduction of second metallic Ru. This work provides a valuable guide for the development of the H2S-tolerant catalysts for long-term application of PEMFCs.

Developing cost‐effective non‐precious metal electrocatalysts (NPMCs) for the sluggish oxygen reduction reaction (ORR) is critical for the large‐scale application of metal‐air battery and fuel cell technologies. Herein, we present an effective Mn/Zn bimetal organic frameworks (MOFs)‐based strategy to synthesize an efficient manganese (Mn) and nitrogen (N) co‐doped porous carbon electrocatalyst with atomically dispersed N‐coordinated single Mn moieties (Mn‐Nx) for ORR catalysis. This strategy involves the adsorption of Mn ions into the Mn/Zn bimetal MOFs followed by the subsequent pyrolysis in Ar and then activation in NH3. Owing to the atomically dispersed Mn‐Nx sites, the large specific surface area and the high content of graphitic‐N, the resulting electrocatalyst shows a superior ORR activity with a half‐wave potential of 0.885 V and an outstanding electrochemical durability in alkaline electrolyte outperforming commercial Pt/C, and it also exhibits a superior performance for an assembled primary Zn–air battery. This work offers a new prospect for the synthesis of MOFs‐derived highly efficient NPMCs for ORR.

Assurance of high-quality hydrogen is critical for end usage in proton-exchange membrane (PEM) fuel cell (PEMFC) electric vehicles with a long lifetime and low cost as a trace amount of CO impurities in hydrogen significantly affects the durability and fuel expense. Herein, we demonstrate an effective strategy to reduce the total ownership cost of PEMFC vehicles by coupling material development and operation optimization, aiming to obtain the optimal tolerance limit for hydrogen impurities. An electrochemical hydrogen pump was used to accurately determine the poisoning-caused overpotential by eliminating interferences from cathode polarization and the permeated oxygen from thin PEM. The quantitative relations of overpotential versus influencing factors (e.g., type of catalysts, CO concentration, and temperature) were established. The results indicate that PtRu/C demonstrates alleviated CO poisoning, exhibiting approximately 12.8 mV lower overpotential than Pt/C after 100 h test (PtRu/C: 6 mV; Pt/C: 18.8 mV) with a CO concentration of 0.2 ppm specified by ISO standards (14687: 2019) and its increase rate of overpotential is reduced to 1/3-fold. Only the electronic effect induced by Pt–Ru interactions is responsible for the improved CO tolerance of PtRu/C under ultra-low CO concentrations, whereas the widely recognized bi-functional effect due to the reaction of Ru–OH with neighboring Pt–CO species does not work, leading to over 10% decrease of CO–Pt(111) adsorption energy for PtRu/C compared with Pt/C. By means of the synergistic effect of the alternative PtRu/C catalyst and an elevated cell temperature at 85 °C, the CO limit can be loosened to 25-fold from currently recommended 0.2 to 5 ppm, which will remarkably decrease the cost of hydrogen purification. This work offers an insight for the cost reduction of hydrogen mobility and the future optimization of hydrogen quality and also provides valuable guidance for the design of robust anti-poisoning CO catalysts for the long-term application of PEMFCs.